1. Field of the Invention
The present invention relates to methods for analyzing nerve fibers distribution, and, more specifically, to a method for analyzing nerve fibers distribution using both the electric current steering technique and the normalized evoked compound action potential (ECAP) technique.
2. Description of Related Art
The electric current steering technique has been applied to cochlear implant (CI) stimulating strategies. In addition, the normalized evoked compound action potential (ECAP) technique has also been used to measure for the neural response in cochlear implant patients.
Referring now to FIG. 1, FIG. 1 shows a schematic diagram depicting the existing ECAP technique. As shown in FIG. 1, an electric current is injected into the group of nerve fibers Nf through the conducting electrode n (El.n). The conducting electrode n+1 (El.n+1) is used to measure and record action potentials Vs of the group of nerve fibers within the stimulation area.
U.S. Patent Application Publication No. 2008/0221640A1 discloses a multi-channel method to elicit electrically-evoked compound action potential (ECAP).
However, it is not possible to use the ECAP technique alone to estimate neural survival based on FIG. 1 or the U.S. Patent Application Publication No. 2008/0221640A1. In other words, even if the stimulation area of FIG. 1 or the U.S. Patent Application Publication No. 2008/0221640A1 covers various nerve fibers, it cannot be rapidly and precisely determined which group of nerve fibers is being activated.
That is to say, the plurality of conducting electrodes are used as the output conducting electrodes (such as El.n+1, El.n+2 and so on). The distance between the group of nerve fibers Nf and each of the plurality of sensing and conducting electrodes may not be the same. Accordingly, the distance between the group of nerve fibers Nf and each of the plurality of sensing and conducting electrodes cannot be precisely computed by the existing techniques.
It can be seen that the existing ECAP technique alone cannot be applied to directly computing a neural distribution. Accordingly, solutions to the problems described above have been long sought, but prior developments have not taught or suggested any solutions and, thus, solutions to the problems have long eluded those skilled in the art. Therefore, there is a heretofore-unaddressed need to overcome defects and shortcomings described above.